Recording device, recording method, reproduction method, and program

ABSTRACT

A recording device includes an imaging data acquisition unit configured to acquire imaging data including video data and audio data imaging an inside of a vehicle or an outside of the vehicle to which the recording device is mounted, an event detection unit configured to detect occurrence of an event for the vehicle, a recording control unit configured to record first imaging data in a recording unit when recording of the imaging data in the recording unit is caused by the event detected by the event detection unit, and record second imaging data in the recording unit when recording of the imaging data in the recording unit is not caused by the event detected by the event detection unit, and a reproduction control unit configured to reproduce the video data and the audio data included in the first imaging data when reproducing the first imaging data.

CROSS REFERENCE TO RELATED APPLICATION

This application is a Continuation of U.S. patent application Ser. No.17/326,137, filed on May 20, 2021, which is a Continuation of U.S.patent application Ser. No. 16/360,904, filed on Mar. 21, 2019, now U.S.Pat. No. 11,050,980, issued on Jun. 29, 2021, which is a BypassContinuation of International Application No. PCT/JP2017/037642 filed onOct. 18, 2017, which is based upon and claims the benefit of priorityfrom Japanese Patent Application No. 2016-225129 filed on Nov. 18, 2016;Japanese Patent Application No. 2016-225130 filed on Nov. 18, 2016; andJapanese Patent Application No. 2017-040029 filed on Mar. 3, 2017, thedisclosures of which are incorporated herein in their entirety byreference.

BACKGROUND

The present disclosure relates to a recording device, a recordingmethod, a reproduction method, and a program.

The number of vehicles equipped with a drive recorder has increased inrecent years. A drive recorder is used as a recording device forrecording imaging data by capturing situations inside or outside avehicle. When a traffic accident happens, the data recorded in the driverecorder may be used in investigation of the cause of an accident. Thedrive recorder continues to constantly record imaging data which iscaptured with a camera or the like, for example, while the engine isrunning. As a result, when the data is fully recorded in a memory deviceup to its capacity, the drive recorder continues to record the newimaging data by overwriting it on the existing imaging data.

Patent Literature 1 (Japanese Unexamined Patent Application PublicationNo. 2016-100672) discloses a configuration of a recording device thatprevents important imaging data at the moment of occurrence of an eventsuch as an accident from being overwritten by imaging data at a normaltime when such an event does not occur. Specifically, according to therecording device disclosed in Patent Literature 1, after the occurrenceof an accident, if the vehicle is in a stopped state, then the recordingis stopped and the overwriting on already recorded imaging data isprevented.

SUMMARY

The imaging data recorded by the recording device disclosed in PatentLiterature 1 or a typical drive recorder (hereinafter referred to as“recording device and the like”) includes image data and audio data. Inaddition, the recording device and the like continue to retain imagingdata even when an engine of a vehicle is stopped. In addition, while onesingle driver uses a vehicle in some cases, multiple drivers orpassengers may use the same vehicle in other cases. In such a case,content of the conversation or content of speeches of multiple userswill be recorded in the recording device and the like, so that a certainuser of the vehicle can eavesdrop on the content of the conversation orthe content of the speeches of other users. This may cause the problemthat the privacy of multiple users using the same vehicle cannot bemaintained.

An embodiment provides a recording device, a recording method, and aprogram capable of retaining imaging data for identifying a cause of anaccident on one hand and protecting privacy of users of a vehicle on theother hand.

A first aspect of the embodiment provides a recording device thatincludes an imaging data acquisition unit configured to acquire imagingdata which includes video data and audio data, an event detection unitconfigured to detect occurrence of an event, and a recording controlunit configured to process the imaging data as first imaging data whichincludes the video data and the audio data when processing on theimaging data is caused by the event that has been detected by the eventdetection unit, and process the imaging data as second imaging datawhich includes the video data but does not include the audio data whenprocessing on the imaging data is not caused by the event.

A second aspect of the embodiment provides a recording method thatincludes acquiring imaging data which includes video data and audiodata, detecting occurrence of an event, processing the imaging data asfirst imaging data including the video data and the audio data whenprocessing on the imaging data is caused by the event that has beendetected, and processing the imaging data as second imaging dataincluding the video data and not including the audio data whenprocessing on the imaging data is not caused by the event.

A third aspect of the embodiment provides a program that causes acomputer to perform acquiring imaging data which includes video data andaudio data, detecting occurrence of an event, processing the imagingdata as first imaging data including the video data and the audio datawhen processing on the imaging data is caused by the event that has beendetected, and processing the imaging data as second imaging dataincluding the video data and not including the audio data whenprocessing on the imaging data is not caused by the event.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a configuration diagram of a recording device according to thefirst embodiment.

FIG. 2 is a diagram illustrating a relationship between data recorded ina recording unit and data recorded in a buffer memory according to thefirst embodiment.

FIG. 3 is a diagram illustrating a flow of recording processing torecord imaging data according to the first embodiment.

FIG. 4 is a configuration diagram of a recording device according to thesecond embodiment.

FIG. 5 is a diagram illustrating a flow of recording processing torecord imaging data according to the second embodiment.

FIG. 6 is a configuration diagram of a recording device according to thethird embodiment.

FIG. 7 is a diagram illustrating a flow of recording processing torecord imaging data according to the third embodiment.

FIG. 8 is a configuration diagram of a recording device according to thefourth embodiment.

FIG. 9 is a diagram illustrating a flow of recording processing torecord imaging data according to the fourth embodiment.

FIG. 10 is a diagram illustrating a relationship between data recordedin a recording unit and data recorded in a buffer memory according tothe fifth embodiment.

FIG. 11 is a diagram illustrating a flow of recording processing torecord imaging data according to the fifth embodiment.

FIG. 12 is a diagram illustrating a flow of reproduction processingaccording to the fifth embodiment.

FIG. 13 is a diagram illustrating a flow of reproduction processingaccording to the sixth embodiment.

FIG. 14 is a diagram illustrating a flow of reproduction processingaccording to the seventh embodiment.

FIG. 15 is a diagram illustrating a flow of reproduction processingaccording to the eighth embodiment.

FIG. 16 is a configuration diagram of a reproduction device according tothe ninth embodiment.

FIG. 17 is a configuration diagram of a recording device according tothe tenth embodiment.

FIG. 18 is a diagram illustrating a relationship between data output tothe transmission control unit and data recorded in a buffer memory 24according to the tenth embodiment.

FIG. 19 is a diagram illustrating a flow of transmission processing totransmit imaging data according to the tenth embodiment.

FIG. 20 is a diagram illustrating a flow of transmission processing totransmit imaging data according to the eleventh embodiment.

FIG. 21 is a diagram for explanation of content of an event detected byan event detection unit according to the eleventh embodiment.

FIG. 22 is a configuration diagram of a recording device according tothe twelfth embodiment.

DETAILED DESCRIPTION First Embodiment

Embodiments of the present disclosure will be described hereinbelow withreference to drawings. An example of a configuration of a recordingdevice 10 according to the first embodiment is described with referenceto FIG. 1 . The recording device 10 may be used, for example, as a driverecorder incorporated in a vehicle. The recording device 10 may be acomputer device operated by its processor executing a program stored inits memory unit. The processor may be, for example, a microprocessor, amicro processing unit (MPU), or a central processing unit (CPU). Thememory unit may be a volatile memory unit or a non-volatile memory unit,or may be configured by combination of a volatile memory unit and anon-volatile memory unit. The processor executes one or more programsincluding a set of instructions for causing the computer to performalgorithms which will be described hereinbelow with reference to thedrawings.

The recording device 10 has a control unit 20, a camera 31, a microphone32, a recording unit 33, a sensor 34, a display unit 35, and a speaker36. The control unit 20 may be directly connected to the camera 31, themicrophone 32, the recording unit 33, the sensor 34, the display unit35, and the speaker 36 using a predetermined cable or the like or may beconnected thereto via a controller area network (CAN) which is anin-vehicle network. Also, the recording device 10 may be configured toinclude a constituent component or components realized by the controlunit 20. Specifically, the recording device 10 includes an imaging dataacquisition unit 21, an event detection unit 22, and a recording controlunit 23.

The camera 31 is configured to generate video data imaging an inside ofthe vehicle or an outside of the vehicle. The microphone 32 isconfigured to collect sounds inside the vehicle or outside the vehicleto generate audio data. The recording unit 33, which may be a hard disk,a card-type memory device, and the like, is configured to record thevideo data and the audio data.

The sensor 34, which is, for example, an acceleration sensor, may beconfigured to detect an impact or the like generated when a vehicleincorporating the recording device 10 causes an accident or is involvedin an accident. Further, the sensor 34 may be configured to detect aspeed, etc. of the vehicle. The display unit 35 may be a display devicethat reproduces the video data recorded in the recording unit 33. Thespeaker 36 is configured to reproduce the audio data recorded in therecording unit 33. The speaker 36 includes an audio amplification unitand a sound processing unit (not shown) before the input of the speaker36 and the speaker 36 includes these units when it is only indicated as“speaker 36.”

Next, an example of the configuration of the control unit 20 will bedescribed. The control unit 20 has an imaging data acquisition unit 21,an event detection unit 22, a recording control unit 23, a buffer memory24, and a reproduction control unit 25. The individual constituentcomponents such as the imaging data acquisition unit 21, the eventdetection unit 22, the recording control unit 23, and the reproductioncontrol unit 25 constituting the control unit 20 may be a softwarecomponent or module whose processing is carried out by the processorexecuting the program stored in the memory unit. Alternatively, theindividual constituent components constituting the control unit 20 maybe a hardware component such as a circuit, a chip, and the like.

The imaging data acquisition unit 21 is configured to acquire the videodata generated by the camera 31 and the audio data generated by themicrophone 32. The data including the video data and the audio data maybe called “imaging data.” In other words, the imaging data acquisitionunit 21 is configured to acquire the imaging data from the camera 31 andthe microphone 32. The video data may be generated using schemes such asH.264 and H.265. Also, the audio data may be generated using a pulsecode modulation (PCM) scheme or the like, and the imaging data which ismoving image data including the video data and the audio data may begenerated using MPEG (Moving Picture Experts Group) 2-TS (TransportStream), AVI (Audio Video Interleave), or the like.

The imaging data acquisition unit 21 is configured to output the imagingdata including the video data and the audio data to the buffer memory24. The buffer memory 24 is configured to temporarily store the outputimaging data. The buffer memory 24 may be called a built-in memory unitincorporated in the control unit 20. To store temporarily in thiscontext may mean, for example, that the buffer memory 24 erases theimaging data after a lapse of a predetermined period. Alternatively, thetemporary storing may mean storing data output from the imaging dataacquisition unit 21 by overwriting it upon the data in the buffer memory24. Alternatively, the temporary storing may mean that the buffer memory24 erases the imaging data that has been output from the imaging dataacquisition unit 21 when the buffer memory 24 output the imaging data tothe recording control unit 23.

The event detection unit 22 is configured to detect occurrence of anevent using information output from the sensor 34. For example, when animpact level detected by the sensor 34 operating as an accelerationsensor exceeds a predetermined value, then the event detection unit 22detects the occurrence of an event “traffic accident.” The impact levelexceeding the predetermined level may be rephrased as an accelerationexceeding a predetermined value. The event detection unit 22, upondetection of the occurrence of the event, outputs the informationindicative of the occurrence of the event to the recording control unit23. The information indicative of the occurrence of the event mayinclude the time point at which the event occurred. Further, theinformation indicative of the occurrence of the event may include thecontent of the event that occurred.

The recording control unit 23 is configured to record the imaging datastored in the buffer memory 24 in the recording unit 33 in a fileformat. The recording control unit 23 records the imaging data acquiredfrom the buffer memory 24 in the recording unit 33 when recording of theimaging data stored in the buffer memory 24 into the recording unit 33is caused by the event that has been detected by the event detectionunit 22. The imaging data acquired from the buffer memory 24 includesthe video data and the audio data. In other words, the recording controlunit 23 is configured to migrate the imaging data from the buffer memory24 to the recording unit 33. When recording of the imaging data storedin the buffer memory 24 into the recording unit 33 is caused by theevent that has been detected by the event detection unit 22, therecording control unit 23 records the imaging data acquired from thebuffer memory 24 on an as-is basis in the recording unit 33.Specifically, the recording control unit 23 generates a moving imagefile including video data and audio data from the imaging data stored inthe buffer memory 24 and records the moving image file in the recordingunit 33.

The recording control unit 23 records the piece of data that onlyincludes the video data into the recording unit 33 from among the piecesof imaging data acquired from the buffer memory 24 when recording of theimaging data stored in the buffer memory 24 into the recording unit 33is not caused by the event that has been detected by the event detectionunit 22. That is, the recording control unit 23 records, in therecording unit 33, the imaging data that includes the video data butdoes not include the audio data. In other words, recording control unit23 records data obtained by erasing audio data from the imaging datafrom the buffer memory 24 into the recording unit 33. Specifically, therecording control unit 23 replaces the audio data in the imaging datastored in the buffer memory 24 by soundless audio data, generates themoving image file by the soundless audio data and the video data, andrecords the moving image file in the recording unit 33.

When the imaging data including the video data and the audio data isrecorded in the recording unit 33, the recording control unit 23 mayrecord imaging data caused by an event, i.e., the imaging data includingthe video data and the audio data into the recording unit 33 asoverwrite-prohibited data. For example, the recording control unit 23may designate an address in a memory area where overwriting of data isprohibited in the recording unit 33 to record the imaging data in therecording unit 33. Alternatively, recording control unit 23 may specifyflag information or the like prohibiting overwriting in the header orpayload of the imaging data.

Also, when the recording control unit 23 records the imaging data thatis not caused by an event, i.e., imaging data from which the audio datais erased so that it only includes the video data, into the recordingunit 33, then the recording control unit 23 may record the imaging datathat only includes the video data into the recording unit 33 asoverwritable data. For example, the recording control unit 23 maydesignate an address in the memory area where overwriting of data isallowed in the recording unit 33 and record the imaging data into therecording unit 33. Alternatively, the recording control unit 23 mayspecify flag information indicating that overwriting is allowed in theheader or payload of the imaging data.

The recording unit 33 records the data that has been output from therecording control unit 23, in other words, data that has been migratedvia the recording control unit 23 from the buffer memory 24.

The reproduction control unit 25 is configured to acquire the imagingdata recorded in the recording unit 33 and output the video data basedon the acquired imaging data to the display unit 35, and output theaudio data based on the acquired imaging data to the speaker 36, etc.

While FIG. 1 illustrates a configuration in which the recording device10 includes the reproduction control unit 25, the display unit 35, andthe speaker 36, a reproduction device or the like different from therecording device 10 may include the reproduction control unit 25, thedisplay unit 35, and the speaker 36. In other words, the recordingdevice 10 may not include the reproduction control unit 25, the displayunit 35, or the speaker 36. That is, a reproduction device or the likethat includes the reproduction control unit 25, the display unit 35, andthe speaker 36 may reproduce the data recorded in the recording unit 33of the recording device 10. For example, the reproduction device or thelike may be a device that reproduces data recorded in a portablerecording medium such as an optical disc and card-type recording medium.The data recorded in the recording unit 33 may be migrated to theportable recording medium.

Here, the relationship between the data recorded in the recording unit33 and the data recorded in the buffer memory 24 is described withreference to FIG. 2 . The horizontal axis illustrated in FIG. 2indicates the passage of time. Each of D−4 to D+2 indicates a piece ofimaging data captured during a predetermined period. In FIG. 2 , D−4 isthe piece of imaging data captured least recently and D+2 is a piece ofimaging data captured most recently. The predetermined period may be,for example, several seconds, several tens of seconds, several minutes,and the like.

The imaging data acquired by the imaging data acquisition unit 21 isimmediately output to the buffer memory 24. As a result, FIG. 2illustrates a configuration in which the imaging data acquired by theimaging data acquisition unit 21 is stored on an as-is basis in thebuffer memory 24. In other words, FIG. 2 illustrates a state where theparticular point of time at which the imaging data acquisition unit 21acquired the imaging data is substantially in agreement with theparticular point of time at which the imaging data was stored in thebuffer memory 24. The substantial agreement in this context may alsoinclude a case where the particular point of time at which the imagingdata acquisition unit 21 acquired the imaging data is not completely inagreement with the particular point of time at which the imaging data isstored in the buffer memory 24. For example, the substantial agreementmay encompass a case where the particular point of time at which theimaging data is stored in the buffer memory 24 may be delayed relativeto the particular point of time at which the imaging data acquisitionunit 21 acquired the imaging data. Meanwhile, the imaging data recordedin the recording unit 33 is temporarily stored in the buffer memory 24and subsequently recorded in the recording unit 33 by the recordingcontrol unit 23. As a result, the particular point of time at which theimaging data acquired by the imaging data acquisition unit 21 is storedin the buffer memory 24 is different from the particular point of timeat which it is recorded in the recording unit 33. Specifically, theparticular point of time at which the imaging data is recorded in therecording unit 33 is later than the particular point of time at whichthe imaging data is stored in the buffer memory 24.

t1 to t6 indicate the time. The recording control unit 23 determineswhether or not an event occurred in the past predetermined periods atthe time t1 to the time t6. For example, the recording control unit 23determines, at the time t2, whether or not an event occurred in theperiod from the time t1 to the time t2. The recording control unit 23likewise determines, at other time points, whether or not an eventoccurred. In FIG. 2 , the recording control unit 23 determines, at thetime t1 to the time t3 and at the time t5, that no event has occurred.Also, the recording control unit 23 at the time t4 determines that anevent has occurred at the time t6 between the time t3 and the time t4.

For example, when the recording control unit 23 determines at the timet2 that no event has occurred in the period from the time t1 to the timet2, then the recording control unit 23 erases the audio data from theimaging data D−2 stored in the buffer memory 24, that is, makes theaudio data soundless in the imaging data D−2, converts the imaging datawhich now includes only the video data into a file and records the filein the recording unit 33. Meanwhile, the recording control unit 23determined at the time t4 that an event occurred at the time t6 in theperiod from the time t3 to the time t4. In this case, the recordingcontrol unit 23 at the time t6 converts the data D stored in the buffermemory 24 into a file on an as-is basis without erasing audio data fromthe data D acquired by the imaging data acquisition unit 21 and recordsthe file in the recording unit 33.

While FIG. 2 illustrates a state where the imaging data storing of whichis completed to the buffer memory 24 is instantaneously recorded in therecording unit 33, the particular point of time at which the imagingdata recorded in the buffer memory 24 is recorded into the recordingunit 33 is not limited to the one illustrated in FIG. 2 . For example,the recording control unit 23 may acquire the imaging data that is beingstored into the buffer memory 24 and record the acquired imaging datainto the recording unit 33. Alternatively, when storing of the imagingdata into the buffer memory 24 has been completed, the recording controlunit 23 may record the same imaging data into the recording unit 33after a lapse of a predetermined period after the time point at whichthe storing of the imaging data was completed. Here, it is intended thatthe imaging data corresponds to any one of D−4 to D+2 illustrated inFIG. 2 .

Also, FIG. 2 illustrates a state where the recording control unit 23records only the imaging data acquired by the imaging data acquisitionunit 21 in a period including the time point at which the event occurredinto the recording unit 33 without erasing the audio data. The recordingcontrol unit 23 is not limited to this and, for example, may record apiece of imaging data acquired by the imaging data acquisition unit 21in a period prior to the period including the time point at which theevent occurred without erasing the audio data into the recording unit 33in addition to the imaging data acquired by the imaging data acquisitionunit 21 in a period including the time point at which the eventoccurred. For example, the recording control unit 23 may record, at thetime t6, data D−1 without erasing audio data into the recording unit 33in addition to the data D acquired by the imaging data acquisition unit21.

Also, even in a case where the recording control unit 23 determines thatno event has occurred, the recording control unit 23 may record in therecording unit 33 the imaging data acquired in a period prior to thelatest period with its audio data erased in addition to the imaging dataacquired in the latest period stored in the buffer memory 24.

In FIG. 2 , the period in which data D−4 to data D−1 are recorded in therecording unit 33 and the period in which data D+1 is recorded aredefined as audio data erasure period and the period in which data D isrecorded in the recording unit 33 is defined as an audio datanon-erasure period.

Next, the flow of the recording processing to record the imaging dataaccording to the first embodiment will be described with reference toFIG. 3 . First, the imaging data acquisition unit 21 outputs the imagingdata including the video data and the audio data to the buffer memory 24and the buffer memory 24 starts storing of the imaging data (S11). Next,the recording control unit 23 determines whether or not an eventoccurred when it starts the recording of the imaging data stored in thebuffer memory 24 into the recording unit 33 (S12). Specifically, therecording control unit 23 determines whether or not an event occurred inthe period of imaging of the imaging data to be migrated. For example,the recording control unit 23 determines whether or not occurrence of anevent was detected by the event detection unit 22 in the period ofimaging of the imaging data to be migrated.

When the recording control unit 23 determines that an event hasoccurred, the recording control unit 23 records the imaging dataincluding the particular point of time at which the event occurred inthe imaging period into the recording unit 33 (S13). The imaging datarecorded in the step S13 is a moving image file that includes video dataand audio data. In other words, the recording control unit 23 convertsthe imaging data into a file without erasing audio data from the imagedata stored in the buffer memory 24 and records the imaging data in therecording unit 33.

When the recording control unit 23 determines that no event hasoccurred, then the recording control unit 23 erases audio data from theimaging data imaged in the period in which no event has occurred andrecords the imaging data that only includes the video data into therecording unit 33 (S14). The imaging data recorded in the step S14 is amoving image file that includes video data and audio data that has beenmade soundless. In other words, the recording control unit 23 erasesaudio data from the imaging data stored in the buffer memory 24 andconverts it into a file, and records the imaging data in the recordingunit 33.

The recording control unit 23, after having recorded the image datastored in the buffer memory 24 in the recording unit 33 in the step S13or S14, determines whether or not image data that is not recorded in therecording unit 33 exists in the buffer memory 24 (S15).

When the recording control unit 23 determines that no imaging data thatis not recorded in the recording unit 33 exists in the buffer memory 24,then the recording control unit 23 terminates the processing. The casewhere no imaging data that is not recorded in the recording unit 33exists in the buffer memory 24 may include, for example, a case where adriver performed an operation to stop the imaging, a case where theengine has stopped and the imaging has been stopped, and other cases.

When the recording control unit 23 determines that imaging data that isnot recorded in the recording unit 33 exists in the buffer memory 24,the recording control unit 23 repeatedly carries out the processingsteps of the step S12 and the subsequent steps.

As described in the foregoing, the recording device 10 according to thefirst embodiment can record video data and audio data in the recordingunit 33 for the imaging data whose imaging period includes theparticular point of time at which the event occurred. Also, with regardto the imaging data imaged in a period in which no event has occurred,the recording device 10 can record only the video data in the recordingunit 33 with the audio data erased from the imaging data. By virtue ofthis, the recording device 10 makes it possible for the imaging data atthe time of occurrence of an event such as a traffic accident tocontribute to identification of the cause of the accident because theimaging data includes the video data and the audio data. On the otherhand, the recording device 10 erases audio data that may includespeeches of the driver or conversations between the driver and apassenger and the like from the imaging data in the period in which noevent has occurred and thus can protect the privacy of the driver andthe passenger.

Further, since the recording device 10 erases audio data from theimaging data in a period in which no event has occurred to record theimaging data in the recording unit 33, it is made possible to reduce theamount of data to be recorded when compared with a case where imagingdata that includes the audio data is to be recorded. By virtue of this,it is made possible to reduce the number of times of overwriting andrecording of the imaging data in the recording unit 33, so that therecording unit 33 can record imaging data in a longer period.

Second Embodiment

Next, an example of a configuration of a recording device 40 accordingto the second embodiment will be described with reference to FIG. 4 .The recording device 40 has a control unit 41 instead of the controlunit 20 of the recording device 10 in FIG. 1 . Also, the control unit 41has a configuration in which a volume level acquisition unit 42 is addedto the control unit 20 of FIG. 1 . With regard to the recording device40, the same reference sings are given to the same features as those ofthe recording device 10 and detailed explanations thereof will not berepeated. The following explanations focus on the features of therecording device 40 different from those of the recording device 10. Therecording device 40 may be configured to include constituent componentsrealized by the control unit 41 in the same manner as the recordingdevice 10.

Specifically, the recording device 40 includes the imaging dataacquisition unit 21, the event detection unit 22, the recording controlunit 23, and the volume level acquisition unit 42.

The volume level acquisition unit 42 is configured to acquireinformation on a volume level from the audio data generated by themicrophone 32. The volume level acquisition unit 42 may acquire theinformation on the volume level from the audio data acquired by theimaging data acquisition unit 21. The volume level may for example beinformation indicative of a volume of a sound. The volume levelacquisition unit 42 outputs the information on the volume level to therecording control unit 23. Specifically, the information on the volumelevel may include identification information to identify the audio data.

While FIG. 4 illustrates a configuration in which the volume levelacquisition unit 42 is arranged between the microphone 32 and therecording control unit 23, the volume level acquisition unit 42 may bearranged between the imaging data acquisition unit 21 and the recordingcontrol unit 23.

When recording of the imaging data stored in the buffer memory 24 intothe recording unit 33 is not caused by the event that has been detectedby the event detection unit 22, the recording control unit 23 determineswhether or not the audio data should be erased from the imaging data inaccordance with the volume level regarding the audio data. For example,a threshold 1 for the volume level is defined between the volume at alevel of normal conversation and a loud voice above the level of normalconversation. That is, the threshold 1 is used to identify a normalconversation level and a volume level above the normal conversationlevel. The loud voice above the level of normal conversation may be, forexample, a human scream or shouting voice, etc.

If the volume level is lower than the threshold 1, the recording controlunit 23 erases the audio data from the imaging data and records only thevideo data in the recording unit 33. Also, if the sound level exceedsthe threshold 1, the recording control unit 23 records the imaging datain the recording unit 33 without erasing the audio data even when noevent has been detected by the event detection unit 22.

Since the recording control unit 23 uses the threshold 1 to determinewhether or not the audio data should be erased from the imaging data, itis made possible to protect privacy of the driver or the passenger.Further, in a case where it is expected that a certain abnormality hasoccurred in the vehicle considering the detection of the loud voiceabove the level of normal conversation although no event is detected bythe sensor 34, or in other similar cases, imaging data including theaudio data can be recorded in the recording unit 33.

Also, a threshold 2 for the volume level may be defined between thevolume at a level of normal conversation and a volume lower than thenormal conversation level. That is, the threshold 2 is used to identifythe normal conversation level and a volume level lower than that. Thevolume lower than the normal conversation level may be, for example,silence or mechanical sound and the like.

If the volume level exceeds the threshold 2, the recording control unit23 erases the audio data from the imaging data and records only thevideo data in the recording unit 33. Also, if the volume level is lowerthan the threshold 2, the recording control unit 23 records the imagingdata in the recording unit 33 without erasing the audio data even whenoccurrence of any event has not been detected by the event detectionunit 22.

Since the recording control unit 23 uses the threshold 2 to determinewhether or not the audio data should be erased from the imaging data, itis made possible to protect privacy of the driver or the passenger.Further, if the sound level corresponds to a sound level that would notreveal the privacy of the driver and the passenger, the imaging datastored in the buffer memory 24 is recorded on an as-is basis in therecording unit 33 without erasure of the audio data, and thereby theprocessing load in the recording control unit 23 can be suppressed.

Also, the recording control unit 23 may use the thresholds 1 and 2 todetermine whether or not the audio data should be erased from theimaging data. For example, the recording control unit 23 records theimaging data in the recording unit 33 without erasing the audio databoth in the case where the volume level exceeds the threshold 1 and, inthe case where it is lower than the threshold 2. Also, the recordingcontrol unit 23 records the imaging data with its audio data erased inthe recording unit 33 in a case where the volume level is lower than thethreshold 1 and exceeds the threshold 2.

Next, the flow of the recording processing to record the imaging dataaccording to the second embodiment will be described with reference toFIG. 5 . Since the steps S21 to S25 are the same as or similar to thesteps S11 to S15 of FIG. 3 , detailed explanations thereof are notrepeated here.

When the recording control unit 23 determines in the step S22 that noevent has occurred, the recording control unit 23 further determineswhether or not the volume level of the audio data included in theimaging data is lower than a predetermined value, e.g., the threshold 1(S26). When the recording control unit 23 determines that the volumelevel exceeds the threshold 1, the recording control unit 23 records, inthe recording unit 33, the imaging data stored in the buffer memory 24without erasing the audio data from the imaging data (S23). When therecording control unit 23 determines that the volume level is lower thanthe threshold 1, the recording control unit 23 records, in the recordingunit 33, the imaging data stored in the buffer memory 24 with the audiodata erased from the imaging data (S24).

While FIG. 5 illustrates processing where the recording control unit 23determines in the step S26 whether or not the volume level is lower thanthe threshold 1, the processing for determining whether or not thevolume level is lower than the threshold 2 may be carried out. In thiscase, when the volume level is lower than the threshold 2, the recordingcontrol unit 23 performs the processing at the step S23, and performsthe processing at the step S24 if the volume level exceeds the threshold2.

Also, the recording control unit 23 may determine whether or not thevolume level is lower than the threshold 1 and exceeds the threshold 2.In this case, if the volume level is lower than the threshold 1 andexceeds the threshold 2, the recording control unit 23 performs theprocessing at the step S24 and performs the processing at the step S23if the condition that the volume level be lower than the threshold 1 andexceeds the threshold 2 is not satisfied.

As described in the foregoing, by using the recording device 40according to the second embodiment, it is made possible to determinewhether or not the audio data should be erased from the imaging data inaccordance with the volume level. By virtue of this, the recordingdevice 40 can estimate that an abnormality has occurred in the vehicleand record the imaging data including the audio data into the recordingunit 33 even when the event detection unit 22 cannot detect an event.Also, even in cases where an event has been detected, depending on thestatus of the conversations in the vehicle, it is possible to create arecord that does not include the audio data, and thus privacy can beensured.

Third Embodiment

Next, an example of a configuration of a recording device 50 accordingto the third embodiment will be described with reference to FIG. 6 . Therecording device 50 includes a control unit 51 instead of the controlunit 20 in the recording device 10 of FIG. 1 . Also, the control unit 51has a configuration in which a speech analysis unit 52 is added to thecontrol unit 20 of FIG. 1 . The same reference signs are given to thesame features of the recording device 50 as those of the recordingdevice 10, and detailed explanations thereof will not be repeated. Thefollowing explanations focus on the features of the recording device 50different from those of the recording device 10. The recording device 50may be configured to include the constituent components realized by thecontrol unit 51 in the same or similar manner as in the recording device10. Specifically, the recording device 50 includes the imaging dataacquisition unit 21, the event detection unit 22, the recording controlunit 23, and the speech analysis unit 52.

The speech analysis unit 52 is configured to determine whether or notthe audio data generated by the microphone 32 includes speech. Thespeech analysis unit 52 may determine whether or not the audio dataacquired by the imaging data acquisition unit 21 includes speech. Speechincludes driver's soliloquy, conversations between a driver and apassenger, etc. The speech analysis unit 52 performs voice recognitionprocessing on the audio data acquired by the imaging data acquisitionunit 21 to detect a sound including a speech component, and therebydetermines whether or not speech is included. The voice recognitionprocessing may be performed using existing voice recognition processingand, for example, a phoneme is extracted from the audio data based on anacoustic model and comparing the extracted phoneme with a linguisticmodel to determine whether or not it is a speech component. Sounds otherthan speech include, for example, a mechanical sound, noise outside thevehicle, etc. The speech analysis unit 52 outputs, along with the audiodata, information indicative of whether or not speech is included in theaudio data to the buffer memory 24. Specifically, the informationindicative of whether or not speech is included therein may includeidentification information for identifying the audio data.Alternatively, the audio data may include information indicative ofwhether or not speech is included.

While FIG. 6 illustrates a configuration in which the speech analysisunit 52 is arranged between the microphone 32 and the recording controlunit 23, the speech analysis unit 52 may be arranged between the imagingdata acquisition unit 21 and the recording control unit 23.

When recording of the imaging data stored in the buffer memory 24 intothe recording unit 33 is not caused by the event that has been detectedby the event detection unit 22, the recording control unit 23 determineswhether or not the audio data should be erased from the imaging data inaccordance with whether or not the audio data includes speech.

If the audio data includes speech, the recording control unit 23 erasesthe audio data from the imaging data and outputs only the video data tothe recording unit 33. Also, if the audio data does not include speech,the recording control unit 23 records the imaging data in the recordingunit 33 without erasing the audio data even when occurrence of an eventis not detected by the event detection unit 22.

Next, the flow of recording processing to record the imaging dataaccording to the third embodiment will be described with reference toFIG. 7 . Since the steps S31 to S35 are the same as or similar to thesteps S11 to S15 of FIG. 3 , detailed explanations thereof will not berepeated.

When the recording control unit 23 determines in the step S32 that noevent has occurred, the recording control unit 23 further determineswhether or not speech is included in the audio data included in theimaging data (S36). When the recording control unit 23 determines thatno speech is included, the recording control unit 23 records, in therecording unit 33, the imaging data stored in the buffer memory 24without erasing the audio data from the imaging data (S33). When therecording control unit 23 determines that speech is included therein,the recording control unit 23 records, in the recording unit 33, theimaging data stored in the buffer memory 24 with the audio data erasedfrom the imaging data (S34).

As described in the foregoing, by using the recording device 50according to the third embodiment, whether or not speech is included inthe audio data can be determined. By virtue of this, the recordingdevice 50 can erase the audio data composed of speech, erasure of whichis most necessary in terms of protection of privacy.

Fourth Embodiment

Next, an example of a configuration of a recording device 60 accordingto the fourth embodiment will be described with reference to FIG. 8 .The recording device 60 includes a control unit 61 instead of thecontrol unit 20 in the recording device 10 of FIG. 1 . Further, therecording device 60 has a sensor 65. Also, the control unit 61 has aconfiguration in which a passenger detection unit 62 is added to thecontrol unit 20 of FIG. 1 . The same reference signs are given to thesame features of the recording device 60 as those of the recordingdevice 10, and detailed explanations thereof will not be repeated. Thefollowing explanations focus on the features of the recording device 60different from those of the recording device 10. The recording device 60may be configured to include the constituent components realized by thecontrol unit 61 in the same or similar manner as in the recording device10. Specifically, the recording device 60 includes the imaging dataacquisition unit 21, the event detection unit 22, the recording controlunit 23, and the passenger detection unit 62.

The sensor 65 is used to detect presence or absence of a passenger otherthan the driver in the vehicle incorporating the recording device 60.The sensor 65 may be a sensor configured to detect, for example, weight.The sensor 65 may be configured to detect the weight of the passengerwhen the passenger is seated on a seat other than the driver's seat.Alternatively, the sensor 65 may be a sensor configured to detectfastening of the seat belt or a sensor configured to detect opening orclosing of a door or doors other than that of the driver's seat. Whenthe sensor 65 has detected the presence of a passenger by the weight ofthe seat other than the driver's seat, opening and closing of the doorother than that of the driver's seat, or any other similar event, thenthe sensor 65 outputs the result of the detection to the passengerdetection unit 62. The sensor 65 may be directly connected using apredetermined cable or connected via a CAN network which is anin-vehicle network.

When the passenger detection unit 62 has received the result of thedetection from the sensor 65, the passenger detection unit 62 outputsthe information indicative of the presence of a passenger other than thedriver in the vehicle incorporating the recording device 60 to therecording control unit 23. The passenger detection unit 62, after havingdetected the presence of the passenger, may output the informationindicative of the presence of the passenger on a periodical basis to therecording control unit 23 while the passenger exists. The periodicalbasis refers, for example, to the cycle shorter than the period ofimaging of the imaging data D−4 to D+2 described in FIG. 2 . In thismanner, since the passenger detection unit 62 outputs the informationindicative of the presence of the passenger to the recording controlunit 23 on a periodical basis, it is made possible to indicate thepresence or absence of the passenger in the period of imaging ofrespective pieces of imaging data D−4 to D+2 described in FIG. 2 evenwhen a passenger exists for a long period of time.

When recording of the imaging data stored in the buffer memory 24 intothe recording unit 33 is not caused by the event that has been detectedby the event detection unit 22, the recording control unit 23 determineswhether or not the audio data should be erased from the imaging data inaccordance with whether or not a passenger exists.

If a passenger exists, the recording control unit 23 erases the audiodata from the imaging data and records only the video data in therecording unit 33. Also, if no passenger exists, the recording controlunit 23 records the imaging data in the recording unit 33 withouterasing the audio data even when occurrence of an event has not beendetected by the event detection unit 22.

Next, the flow of recording processing to record the imaging dataaccording to the fourth embodiment will be described with reference toFIG. 9 . Since the steps S41 to S45 are the same as or similar to thesteps S11 to S15 of FIG. 3 , detailed explanations thereof will not berepeated.

When the recording control unit 23 determines in the step S42 that noevent has occurred, the recording control unit 23 further determineswhether or not a passenger exists (S46). When the recording control unit23 determines that no passenger exists, the recording control unit 23records, in the recording unit 33, the imaging data stored in the buffermemory 24 without erasing the audio data from the imaging data (S43).When the recording control unit 23 determines that a passenger exists,the recording control unit 23 records, in the recording unit 33, theimaging data stored in the buffer memory 24 with the audio data erasedfrom the imaging data (S44).

As described in the foregoing, by using the recording device 60according to the fourth embodiment, it is made possible to determinewhether or not a passenger exists in the vehicle incorporating therecording device 60. By virtue of this, the recording device 60 canerase audio data in a situation where any conversation with a passengermay occur in terms of protection of privacy of the driver and thepassenger.

Fifth Embodiment

Next, an example of a configuration of a recording device 10 accordingto the fifth embodiment will be described with reference to FIG. 1 .Here, detailed explanations will not be repeated regarding the same orsimilar content as the configuration of the recording device 10described in the first embodiment, and the following explanations focuson the processing or the like different from that which is performed bythe recording device 10 described in the first embodiment. Also, therecording device 10 may be configured to include the constituentcomponents realized by the control unit 20. Specifically, the recordingdevice 10 includes the imaging data acquisition unit 21, the eventdetection unit 22, the recording control unit 23, and the reproductioncontrol unit 25.

In the recording device 10 according to the fifth embodiment, therecording control unit 23 records the imaging data stored in the buffermemory 24 in a file format into the recording unit 33. The recordingcontrol unit 23 records imaging data to be recorded in the recordingunit 33, recording of which is caused by the event that has beendetected by the event detection unit 22 (hereinafter called “eventimaging data”) and imaging data to be recorded in the recording unit 33,recording of which is not caused by the event that has been detected bythe event detection unit 22 (hereinafter referred to as “non-eventimaging data”) in the recording unit 33 in such a manner that they aredistinguished from each other. Recording the event imaging data and thenon-event imaging data in the recording unit 33 such that they aredistinguished from each other may imply, for example, that a memory areain the recording unit 33 where the event imaging data is to be recordedis different than a memory area in the recording unit 33 where thenon-event imaging data is to be recorded. Specifically, the recordingcontrol unit 23 designates the address of the memory area in therecording unit 33 in which the event imaging data is to be recorded soas to record the event imaging data in the recording unit 33. Also, therecording control unit 23 designates the address of the memory area inthe recording unit 33 in which the non-event imaging data is to berecorded so as to record the non-event imaging data in the recordingunit 33. Specifically, the recording control unit 23 generates, from theimaging data stored in the buffer memory 24, a moving image fileincluding the video data and the audio data and records it in therecording unit 33.

Alternatively, recording the event imaging data and the non-eventimaging data in the recording unit 33 such that they are distinguishedfrom each other may include specifying, by the recording control unit23, flag information or the like indicating that this is event imagingdata in the header or the payload of the event imaging data. Also, therecording control unit 23 may specify flag information or the likeindicating that this is non-event imaging data in the header or thepayload of the non-event imaging data or may not specify the flaginformation. That is, the imaging data for which the flag information isnot specified may be recognized as non-event imaging data. In contrast,when the flag information indicating that this is non-event imaging datais specified in the header or the payload of the non-event imaging data,the flag information does not need to be specified for the event imagingdata.

Also, the recording control unit 23 may record the event imaging data inthe recording unit 33 as overwrite-prohibited data. For example, therecording control unit 23 may designate an address of a memory area inthe recording unit 33 where overwriting of data is prohibited so as torecord the event imaging data in the recording unit 33. Alternatively,the recording control unit 23 may specify flag information or the likeindicating that overwriting is prohibited in the header or the payloadof the event imaging data. The memory area in the recording unit 33where overwriting of data is prohibited and the address of the memoryarea in the recording unit 33 in which the event imaging data is to berecorded may be identical with each other and either of these memoryareas may be included in the other memory area.

Further, the recording control unit 23 may record the non-event imagingdata in the recording unit 33 as overwritable data. For example, therecording control unit 23 may designate an address of a memory area inthe recording unit 33 where overwriting of data is allowed so as torecord the non-event imaging data in the recording unit 33.Alternatively, recording control unit 23 may specify flag informationindicating that overwriting is allowed in the header or payload of thenon-event imaging data. The memory area in the recording unit 33 whereoverwriting of data is allowed and the address of the memory area in therecording unit 33 where the non-event imaging data is to be recorded maybe identical with each other and either of these memory areas may beincluded in the other memory area.

The recording unit 33 records the data that has been output from therecording control unit 23, in other words, data that has been migratedvia the recording control unit 23 from the buffer memory 24.

The reproduction control unit 25 acquires the imaging data recorded inthe recording unit 33, outputs the video data based on the acquiredimaging data to the display unit 35, and outputs the audio data based onthe acquired imaging data to the speaker 36, etc. When the reproductioncontrol unit 25 reproduces the event imaging data, the reproductioncontrol unit 25 outputs the video data included in the event imagingdata to the display unit 35 and outputs the audio data included in theevent imaging data to the speaker 36, etc. When the reproduction controlunit 25 reproduces non-event imaging data, the reproduction control unit25 outputs the video data included in the non-event imaging data to thedisplay unit 35 but does not output the audio data included in thenon-event imaging data to the speaker 36, etc.

When the reproduction control unit 25 has received a reproductioninstruction information instructing reproduction of event imaging dataentered by a user operating the recording device 10, then thereproduction control unit 25 acquires the event imaging data which theuser wants to reproduce from the memory area in the recording unit 33where the event imaging data is to be recorded. Alternatively, when thereproduction control unit 25 has received a reproduction instructioninformation instructing reproduction of event imaging data entered bythe user operating the recording device 10, the reproduction controlunit 25 extracts event imaging data having flag information indicatingthat this is event imaging data. Further, the reproduction control unit25 selects the event imaging data that the user wants to reproduce fromamong the pieces of event imaging data that have been extracted.

When the reproduction control unit 25 has received a reproductioninstruction information instructing reproduction of non-event imagingdata entered by a user operating the recording device 10, then thereproduction control unit 25 acquires the non-event imaging data whichthe user wants to reproduce from the memory area in the recording unit33 where the non-event imaging data is to be recorded. At this point,the reproduction control unit 25 may acquire only the video dataincluded in the non-event imaging data. Alternatively, the reproductioncontrol unit 25 may acquire the video data and the audio data includedin the non-event imaging data and output only the video data to thedisplay unit 35. Alternatively, the reproduction control unit 25 mayacquire the video data and the audio data included in the non-eventimaging data and output the video data to the display unit 35 and outputthe audio data to the speaker 36, etc. with its output level set tozero.

When the reproduction control unit 25 has received a reproductioninstruction information instructing reproduction of non-event imagingdata entered by the user operating the recording device 10, then thereproduction control unit 25 extracts non-event imaging data having flaginformation indicating that this is non-event imaging data. Further, thereproduction control unit 25 selects the non-event imaging data whichthe user wants to reproduce from among the pieces of non-event imagingdata that have been extracted. At this point, the reproduction controlunit 25 may acquire only the video data included in the non-eventimaging data that have been selected. Alternatively, reproductioncontrol unit 25 may acquire the video data and the audio data includedin the non-event imaging data that has been selected and output only thevideo data to the display unit 35.

Here, the relationship between the data recorded in the recording unit33 and the data recorded in the buffer memory 24 will be described withreference to FIG. 10 . Here, detailed explanations of the content commonto FIGS. 10 and 2 are omitted and the explanations focus on the contentdifferent from that in FIG. 2 .

When the recording control unit 23 determines, for example, at the timet2 that no event has occurred in the period from the time t1 to the timet2, then the recording control unit 23 records the imaging data D−2 inthe recording unit 33 as non-event imaging data. Specifically, therecording control unit 23 designates the address of the memory area inthe recording unit 33 in which the non-event imaging data is to berecorded so as to record the imaging data D−2 stored in the buffermemory 24 in the recording unit 33 as non-event imaging data.

Alternatively, the recording control unit 23 specifies the flaginformation indicating that this is non-event imaging data in the headeror the payload of the imaging data D−2 stored in the buffer memory 24and records the imaging data D−2 in the recording unit 33 as non-eventimaging data.

Meanwhile, when the recording control unit 23 determines at the time t4that an event occurred at the time t6 in the period from the time t3 tothe time t4, then the recording control unit 23 records the imaging dataD in the recording unit 33 as event imaging data. Specifically, therecording control unit 23 designates the address of the memory area inthe recording unit 33 in which the event imaging data is to be recordedso as to record the imaging data D stored in the buffer memory 24 in therecording unit 33 as event imaging data. Alternatively, the recordingcontrol unit 23 specifies flag information indicating that this is eventimaging data in the header or the payload of the imaging data D storedin the buffer memory 24 and records the imaging data D in the recordingunit 33 as event imaging data.

Also, FIG. 10 illustrates a configuration in which the recording controlunit 23 records only the imaging data acquired by the imaging dataacquisition unit 21 in a period including the time point at which theevent occurred into the recording unit 33 as event imaging data. Therecording control unit 23 is not limited to this and, for example, mayrecord, in addition to the imaging data acquired by the imaging dataacquisition unit 21 in a period including the time point at which theevent occurred, the imaging data acquired by the imaging dataacquisition unit 21 in a period prior to the period including the timepoint at which the event occurred in the recording unit 33 as eventimaging data. For example, the recording control unit 23 may record atthe time t6, in addition to the data D acquired by the imaging dataacquisition unit 21, the data D−1 in the recording unit 33 as eventimaging data.

Also, when the recording control unit 23 determines that no event hasoccurred, the recording control unit 23 may also record the imaging dataacquired in a period prior to the latest period in the recording unit 33as non-event imaging data in addition to the imaging data acquired inthe latest period stored in the buffer memory 24.

In FIG. 10 , pieces of data D−4 to D−1 and data D+1 are recorded asnon-event imaging data in the recording unit 33 and the piece of data Dis recorded as event imaging data in the recording unit 33.

Next, the flow of the recording processing to record the imaging dataaccording to the fifth embodiment will be described with reference toFIG. 11 . Since the steps S51 and S52 are the same as or similar to thesteps S11 and S12 of FIG. 3 , detailed explanations thereof will not berepeated.

When the recording control unit 23 determines in the step S52 that anevent has occurred, the recording control unit 23 records the imagingdata in the recording unit 33 as event imaging data (S53). When therecording control unit 23 determines in the step S52 that no event hasoccurred, the recording control unit 23 records the imaging data in therecording unit 33 as non-event imaging data (S54). That is, therecording control unit 23 records the imaging data in the recordingcontrol unit 23 such that the event imaging data and the non-eventimaging data are distinguished from each other.

Since the step S55 is the same as or similar to the step S15 of FIG. 3 ,detailed explanations thereof will not be repeated.

Next, the flow of reproduction processing for reproducing the imagingdata according to the fifth embodiment will be described with referenceto FIG. 12 . First, the reproduction control unit 25 determines whetheror not the reproduction instruction information has been received (S61).The reproduction control unit 25 may receive reproduction instructioninformation that has been entered by a user operating the recordingdevice 10. When the reproduction control unit 25 determines that thereproduction instruction information has not been received, theprocessing at the step S61 will be repeated.

When the reproduction control unit 25 determines in the step S61 thatthe reproduction instruction information has been received, thereproduction control unit 25 determines whether or not the reproductionof the event imaging data which is the imaging data in the eventoccurrence period is instructed (S62). It is assumed here that thereproduction instruction information includes information indicative ofthe period of imaging of the imaging data and information indicative ofwhether or not the reproduction is reproduction of event imaging data orreproduction of non-event imaging data.

Alternatively, the reproduction control unit 25 may acquire in the stepS62 the imaging data reproduction of which has been instructed from therecording unit 33 and determine whether the imaging data that has beenacquired is event imaging data or non-event imaging data. Thereproduction control unit 25 identifies the imaging data recorded in therecording unit 33, for example, by using information indicative of theperiod of imaging of the imaging data included in the reproductioninstruction information. The reproduction control unit 25 may determinewhether or not the imaging data reproduction of which has beeninstructed is event imaging data or non-event imaging data in accordancewith the specific memory area in the recording unit 33 where the imagingdata reproduction of which has been instructed is recorded.Alternatively, the reproduction control unit 25 may determine whether ornot the imaging data reproduction of which has been instructed is eventimaging data or non-event imaging data on the basis of the flaginformation specified in the imaging data reproduction of which has beeninstructed.

When the reproduction control unit 25 determines in the step S62 thatthe reproduction of the event imaging data has been instructed, thereproduction control unit 25 outputs the instructed video data includedin the event imaging data to the display unit 35 and outputs the audiodata to the speaker 36 (S63).

When the reproduction control unit 25 determines in the step S62 thatthe reproduction of the event imaging data is not instructed, in otherwords, determines that reproduction of the non-event imaging data isinstructed, then the reproduction control unit 25 outputs the video dataincluded in the non-event imaging data that has been instructed to thedisplay unit 35 (S64). In this case, the reproduction control unit 25does not output the audio data included in the non-event imaging data tothe speaker 36.

After having performed the processing at the step S63 or S64, thereproduction control unit 25 determines whether or not reproduction ofthe event imaging data or the non-event imaging data has been completed(S65). When the reproduction control unit 25 determines thatreproduction of the event imaging data or the non-event imaging data hasbeen completed, the reproduction control unit 25 terminates thereproduction processing. When the reproduction control unit 25determines that reproduction of the event imaging data or the non-eventimaging data has not been completed, the reproduction control unit 25repeats the processing at the step S65 until the reproduction iscompleted.

As described in the foregoing, the recording device 10 according to thefifth embodiment can reproduce the video data and the audio dataregarding the imaging data whose period of imaging includes theparticular point of time at which the event occurred. Also, therecording device 10 can reproduce only the video data withoutreproducing the audio data regarding the imaging data imaged in a periodin which no event occurred. By virtue of this, the recording device 10makes it possible for the imaging data at the time of occurrence of anevent such as a traffic accident to contribute to identification of thecause of the accident because the imaging data includes the video dataand the audio data. On the other hand, the recording device 10 does notreproduce audio data that may include speeches of a drivers orconversations between the driver and the passenger and the like withregard to the imaging data in the period in which no event has occurredand thus can protect the privacy of the driver and the passenger.

Sixth Embodiment

Next, an example of a configuration of a recording device 40 accordingto the sixth embodiment will be described with reference to FIG. 4 .Here, detailed explanations will not be repeated regarding the same orsimilar content as the configuration of the recording device 40described in the second embodiment, and the following explanations focuson the processing or the like different from that which is performed bythe recording device 40 described in the second embodiment. Also, therecording device 40 may be configured to include the constituentcomponents realized by the control unit 41. Specifically, the recordingdevice 40 includes the imaging data acquisition unit 21, the eventdetection unit 22, the recording control unit 23, the reproductioncontrol unit 25, and the volume level acquisition unit 42.

While FIG. 4 illustrates a configuration in which the volume levelacquisition unit 42 is arranged between the microphone 32 and therecording control unit 23, the volume level acquisition unit 42 may bearranged between the imaging data acquisition unit 21 and the recordingcontrol unit 23, or may be arranged between the recording unit 33 andthe reproduction control unit 25.

When recording of the imaging data stored in the buffer memory 24 intothe recording unit 33 is not caused by the event that has been detectedby the event detection unit 22, the recording control unit 23 recordsthe imaging data as non-event imaging data and further records theinformation on the volume level of the audio data in the recording unit33.

When the reproduction control unit 25 reproduces the event imaging data,the reproduction control unit 25 outputs the video data included in theevent imaging data to the display unit 35 and outputs the audio dataincluded in the event imaging data to the speaker 36.

When the reproduction control unit 25 reproduces the non-event imagingdata, the reproduction control unit 25 determines whether or not theaudio data should be reproduced in accordance with the volume level ofthe audio data. For example, the reproduction control unit 25 has athreshold 1 for the volume level between the volume at a level of normalconversation and a loud voice above the level of normal conversation.That is, the threshold 1 is used to identify a normal conversation leveland a volume level above the normal conversation level. The loud voiceabove the level of normal conversation may be, for example, a humanscream or shouting voice, etc.

If the volume level is lower than the threshold 1, the reproductioncontrol unit 25 does not reproduce the audio data included in thenon-event imaging data. Also, if the sound level exceeds the threshold1, the reproduction control unit 25 reproduces the audio data includedin the non-event imaging data even when the occurrence of the event hasnot been detected by the event detection unit 22.

Since the reproduction control unit 25 uses the threshold 1 to determinewhether or not the audio data included in the non-event imaging datashould be reproduced, privacy of the driver or passenger can beprotected. That is, if the audio data included in the non-event imagingdata includes the volume level of the normal conversation level, theaudio data is not reproduced, so that the privacy of the driver orpassenger is protected. Also, in a case where it is expected that acertain abnormality has occurred in the vehicle considering thedetection of a loud voice above the level of normal conversationalthough no event is detected by the sensor 34, or in other similarcases, the reproduction control unit 25 can reproduce the audio dataalong with the video data included in the non-event imaging data.

Also, the reproduction control unit 25 may have a threshold 2 for thevolume level between the volume at a level of normal conversation andthe volume lower than the normal conversation level. That is, thethreshold 2 is used to identify the normal conversation level and avolume level lower than that.

The volume lower than the normal conversation level may be, for example,silence or mechanical sound, and the like.

If the volume level exceeds the threshold 2, the reproduction controlunit 25 does not reproduce the audio data included in the non-eventimaging data. Also, if the sound level is lower than the threshold 2,the reproduction control unit 25 reproduces the audio data included inthe non-event imaging data even when the occurrence of the event has notbeen detected by the event detection unit 22.

Since the reproduction control unit 25 uses the threshold 2 to determinewhether or not the audio data included in the non-event imaging datashould be reproduced, privacy of the driver or passenger can beprotected. That is, the audio data is not reproduced if the audio dataincluded in the non-event imaging data includes the volume level of thenormal conversation level, so that the privacy of the driver orpassenger is protected.

Further, if the sound level falls within the range that would not revealthe privacy of the driver and the passenger, the reproduction controlunit 25 outputs the video data and the audio data to the display unit 35and the speaker 36. Such processing is of an ordinary nature forreproducing imaging data, the processing load in the reproductioncontrol unit 25 can be suppressed.

Also, the reproduction control unit 25 may use the thresholds 1 and 2 todetermine whether or not the audio data included in the non-eventimaging data should be reproduced. For example, the reproduction controlunit 25 outputs the video data included in the non-event imaging data tothe display unit 35, and outputs the audio data to the speaker 36 bothin the case where the volume level exceeds the threshold 1 and in thecase where it is lower than the threshold 2. Also, the display unit 35outputs only the video data included in the non-event imaging data tothe display unit 35 but does not output the audio data to the speaker 36in a case where the volume level is lower than the threshold 1 andexceeds the threshold 2.

Next, the flow of the reproduction processing according to the sixthembodiment will be described with reference to FIG. 13 . Since the stepsS71 to S75 are the same as or similar to the steps S61 to S65 of FIG. 12, detailed explanations thereof will not be repeated.

When the reproduction control unit 25 determines in the step S72 thatreproduction of the non-event imaging data is instructed, thereproduction control unit 25 determines whether or not the volume levelof the audio data included in the non-event imaging data is lower thanthe threshold 1 (S76).

When the reproduction control unit 25 determines that the volume levelis lower than the threshold 1, the reproduction control unit 25 outputsonly the video data to the display unit 35 without outputting the audiodata included in the non-event imaging data to the speaker 36 (S74).When the reproduction control unit 25 determines that the volume levelexceeds the threshold 1, the reproduction control unit 25 outputs thevideo data included in the non-event imaging data to the display unit35, and outputs the audio data to the speaker 36 (S73).

While FIG. 13 illustrates the processing according to which, in the stepS76, the reproduction control unit 25 determines whether or not thevolume level is lower than the threshold 1, it may perform theprocessing for determining whether or not the volume level is lower thanthe threshold 2. In this case, the reproduction control unit 25 performsthe processing at the step S73 if the volume level is lower than thethreshold 2 and performs the processing at the step S74 if the volumelevel exceeds the threshold 2.

Also, the reproduction control unit 25 may determine whether or not thevolume level is lower than the threshold 1 and exceeds the threshold 2.In this case, the reproduction control unit 25 performs the processingat the step S74 if the volume level is lower than the threshold 1 andexceeds the threshold 2 and performs the processing at the step S73 ifthe condition that the volume level be lower than the threshold 1 andexceed the threshold 2 is not satisfied.

As described in the foregoing, the recording device 40 according to thesixth embodiment can reproduce the video data and the audio data for theimaging data whose period of imaging includes the particular point oftime at which the event occurred. Also, the recording device 40 canprevent reproduction of audio data having a volume level of a normalconversation level for the imaging data imaged in a period where noevent has occurred. By virtue of this, the recording device 40 canprotect the privacy of the driver and the passenger. On the other hand,the recording device 40 can reproduce the audio data having volume levelthat implies that an abnormality occurred in the vehicle, i.e., thevolume level equal to or higher than the normal conversation level forthe imaging data imaged in a period where no event has occurred. Byvirtue of this, the recording device 40 makes it possible for thenon-event imaging data to contribute to identification of the cause of acertain abnormality occurring in the vehicle.

Seventh Embodiment

Next, an example of a configuration of a recording device 50 accordingto the seventh embodiment will be described with reference to FIG. 6 .Here, detailed explanations will not be repeated regarding the same orsimilar content as the configuration of the recording device 50described in the third embodiment, and the following explanations focuson the processing or the like different from that which is performed bythe recording device 50 described in the third embodiment. Also, therecording device 50 may be configured to include the constituentcomponents realized by the control unit 51. Specifically, the recordingdevice 50 includes the imaging data acquisition unit 21, the eventdetection unit 22, the recording control unit 23, the reproductioncontrol unit 25, and the speech analysis unit 52.

While FIG. 6 illustrates a configuration in which the speech analysisunit 52 is arranged between the microphone 32 and the recording controlunit 23, the speech analysis unit 52 may be arranged between the imagingdata acquisition unit 21 and the recording control unit 23, or may bearranged between the recording unit 33 and the reproduction control unit25.

When recording of the imaging data stored in the buffer memory 24 intothe recording unit 33 is not caused by the event that has been detectedby the event detection unit 22, then the recording control unit 23records the imaging data as non-event imaging data and records theinformation on whether or not speech is included in the audio data inthe recording unit 33.

When the reproduction control unit 25 reproduces the event imaging data,the reproduction control unit 25 outputs the video data included in theevent imaging data to the display unit 35 and outputs the audio dataincluded in the event imaging data to the speaker 36.

When the reproduction control unit 25 reproduces non-event imaging data,the reproduction control unit 25 determines whether or not the audiodata should be reproduced in accordance with whether or not speech isincluded in the audio data. When the reproduction control unit 25reproduces non-event imaging data, the reproduction control unit 25outputs video data to the display unit 35 without outputting audio datato the speaker 36 if speech is included in the audio data.

Next, the flow of the reproduction processing according to the seventhembodiment will be described with reference to FIG. 14 . Since the stepsS81 to.

S85 are the same as or similar to the steps S61 to S65 of FIG. 12 ,detailed explanations thereof will not be repeated.

When the reproduction control unit 25 determines in the step S82 thatthe reproduction of the non-event imaging data is instructed, thereproduction control unit 25 determines whether or not speech isincluded in the audio data included in the non-event imaging data (S86).

When the reproduction control unit 25 determines that speech isincluded, the reproduction control unit 25 does not output the audiodata included in the non-event imaging data to the speaker 36 andoutputs only the video data to the display unit 35 (S84). When thereproduction control unit 25 determines that no speech is included, thenthe reproduction control unit 25 outputs the video data and audio dataincluded in the non-event imaging data to the display unit 35 and thespeaker 36 (S83).

As described in the foregoing, by using the recording device 50according to the seventh embodiment, it is made possible to determinewhether or not speech is included in the audio data. By virtue of this,recording device 50, it is made possible to avoid reproduction of audiodata including speech whose reproduction is least desirable in terms ofprotection of privacy.

Eighth Embodiment

Next, an example of a configuration of a recording device 60 accordingto the eighth embodiment will be described with reference to FIG. 8 .Here, detailed explanations will not be repeated regarding the same orsimilar content as the configuration of the recording device 60described in the fourth embodiment, and the following explanations focuson the processing or the like different from that which is performed bythe recording device 60 described in the fourth embodiment. Also, therecording device 60 may be configured to include the constituentcomponents realized by the control unit 61. Specifically, the recordingdevice 60 includes the imaging data acquisition unit 21, the eventdetection unit 22, the recording control unit 23, the reproductioncontrol unit 25, and the passenger detection unit 62.

When recording of the imaging data stored in the buffer memory 24 intothe recording unit 33 is not caused by the event that has been detectedby the event detection unit 22, the recording control unit 23 recordsthe imaging data as non-event imaging data and further records theinformation on whether or not a passenger exists in the recording unit33.

When the reproduction control unit 25 reproduces the event imaging data,the reproduction control unit 25 outputs the video data included in theevent imaging data to the display unit 35 and outputs the audio dataincluded in the event imaging data to the speaker 36.

When the reproduction control unit 25 reproduces the non-event imagingdata, the reproduction control unit 25 determines whether or not theaudio data should be reproduced in accordance with whether or not apassenger exists in the vehicle that incorporates the recording device60. When the reproduction control unit 25 reproduces the non-eventimaging data that has been acquired while a passenger exists, thereproduction control unit 25 outputs the video data to the display unit35 without outputting the audio data to the speaker 36.

Next, the flow of the reproduction processing according to the eighthembodiment will be described with reference to FIG. 15 . Since the stepsS91 to S95 are the same as or similar to the steps S61 to S65 of FIG. 12, detailed explanations thereof will not be repeated.

When the reproduction control unit 25 determines in the step S92 thatthe reproduction of the non-event imaging data is instructed, then thereproduction control unit 25 determines whether or not a passengerexisted when the same non-event imaging data was acquired (S96).

When the reproduction control unit 25 determined that a passenger hadexisted, the reproduction control unit 25 outputs only the video data tothe display unit 35 without outputting the audio data included in thenon-event imaging data on the speaker 36 (S94). When the reproductioncontrol unit 25 determined that no passenger had existed, thereproduction control unit 25 outputs the video data included in thenon-event imaging data to the display unit 35 and outputs the audio datato the speaker 36 (S93).

As described in the foregoing, by using the recording device 60according to the eighth embodiment, it is made possible to determinewhether or not a passenger existed when the non-event imaging data whosereproduction is requested was acquired. By virtue of this, recordingdevice 60 can avoid reproduction of audio data in a situation where aconversation with a passenger may occur in terms of protection ofprivacy.

Ninth Embodiment

Next, an example of a configuration of a reproduction device 70according to the ninth embodiment will be described with reference toFIG. 16 . The reproduction device 70 is a device that reproduces theevent imaging data and the non-event imaging data recorded in therecording unit 33 in the recording device 10, the recording device 40,the recording device 50, and the recording device 60 (hereinafter called“recording device 10, etc.”) which have been described in Embodiments 5to 8.

For example, the recording device 10, etc. records the event imagingdata and the non-event imaging data recorded in the recording unit 33 ina portable recording medium such as an optical disc or a card-typerecording medium. The portable recording medium may have a memory areafor recording the event imaging data and a memory area for recording anon-event imaging data, where these memory areas are separated from eachother. In this case, the recording device 10 records the event imagingdata recorded in the recording unit 33 into the memory area of theportable recording medium for recording the event imaging data. Also,the recording device 10 records the non-event imaging data recorded inthe recording unit 33 into the memory area of the portable recordingmedium for recording the non-event imaging data.

Alternatively, it is assumed here that flag information for identifyingevent imaging data and non-event imaging data is specified in the eventimaging data and the non-event imaging data recorded in the recordingunit 33. In this case, the memory area in the portable recording mediumdoes not need to be divided into a memory area for recording eventimaging data and memory area for recording non-event imaging data.

The reproduction device 70 is configured to reproduce event imaging dataand non-event imaging data recorded in a recording medium. Thereproduction device 70 may be a computer device that operates by itsprocessor executing a program stored in its memory unit. For example,the reproduction device 70 may be a mobile phone terminal, a smartphoneterminal, a personal computer, or the like. Further, the reproductiondevice 70 may be a video camera, a digital camera, a recording andreproduction device of home or business use, and the like.

Here, an example of a configuration of the reproduction device 70 willbe described. The reproduction device 70 has a data reading unit 71, areproduction control unit 72, a display unit 73, and a speaker 74. Thedisplay unit 73 is the same as or similar to the display unit 35 of therecording device 10, etc. and the speaker 74 is the same as or similarto the speaker 36 of the recording device 10, etc., so that detailedexplanations thereof will not be repeated. The data reading unit 71 andthe reproduction control unit 72 may be software or a module whoseprocessing is carried out by the processor executing the program storedin the memory unit. Alternatively, the data reading unit 71 and thereproduction control unit 72 may be a hardware component such as acircuit, a chip, and the like.

The data reading unit 71 is configured to read data recorded in theportable recording medium and decode the data that has been read. Thedata reading unit 71 is also configured to output the data that has beendecoded to the reproduction control unit 72. When the reproductioncontrol unit 72 reproduces event imaging data, the reproduction controlunit 72 outputs the video data included in the event imaging data to thedisplay unit 73 and outputs the audio data to the speaker 74.

When the data reading unit 71 read the data from the memory area thatstores event imaging data, the data reading unit 71 outputs informationindicating that this is event imaging data to the reproduction controlunit 72 along with the decoded data. When the data reading unit 71 readdata from the memory area that stores non-event imaging data, the datareading unit 71 outputs information indicating that this is non-eventimaging data to the reproduction control unit 72 along with the decodeddata.

When data including the flag information for identifying the eventimaging data and the non-event imaging data is recorded in the portablerecording medium, the data that has been decoded by the data readingunit 71 also includes the flag information for identifying the eventimaging data and the non-event imaging data.

When the reproduction control unit 72 reproduces non-event imaging data,the reproduction control unit 72 outputs the video data to the displayunit 73 without outputting the audio data included in the event imagingdata to the speaker 74.

The reproduction control unit 72 specifically may perform thereproduction processing which have been described in FIGS. 12 to 15 .

As described in the foregoing, the reproduction device of FIG. 16 iscapable of reproducing the event imaging data and the non-event imagingdata recorded in the recording device 10, etc. In other words, a usercan reproduce the event imaging data and the non-event imaging datarecorded by the recording device 10, etc. on the reproduction device 70which is a device different than the recording device 10, etc. As aresult, the user does not need to reproduce the event imaging data andthe non-event imaging data recorded by the recording device 10, etc. onthe same recording device 10. As result of this, the user can enjoyimproved usability.

Tenth Embodiment

Next, an example of a configuration of a recording device 80 accordingto the tenth embodiment will be described with reference to FIG. 17 .The recording device 80 has a control unit 81 instead of the controlunit 20 in the recording device 10 of FIG. 1 . Further, the recordingdevice 80 is configured by removing the recording unit 33 from therecording device 10 of FIG. 1 and adding a communication unit 37thereto. Also, the control unit 81 has a configuration in which atransmission control unit 28 and a reception control unit 29 are addedto the control unit 20 of FIG. 1 . Also, the communication unit 37 has atransmission unit 38 and a reception unit 39. With regard to therecording device 80, the same reference signs are given to the samefeatures as those of the recording device 10, and detailed explanationsthereof will not be repeated. The following explanations focus on thefeatures of the recording device 80 different from those of therecording device 10. The recording device 80 may be configured toinclude the constituent components realized by the control unit 81 inthe same or similar manner as in the recording device 10. Specifically,the recording device 80 includes the imaging data acquisition unit 21,the event detection unit 22, the recording control unit 23, thetransmission control unit 28, and the reception control unit 29.

Also, the recording device 80 is configured to perform communicationswith the external recording device 5 via a network. Specifically, therecording device 80 transmits the imaging data imaged using the camera31 and the microphone 32 to the external recording device 5. In otherwords, the recording device 80 records the imaging data in the externalrecording device 5. The external recording device 5 may be a serverdevice such as a cloud server and may be a server device managed by acompany or an individual. Alternatively, the external recording device 5may be a computer device such as a personal computer. The externalrecording device 5 records the imaging data that has been received viathe network.

The sensor 34, which is, for example, an acceleration sensor, may detectan impact or the like occurring in a case where the vehicleincorporating the recording device 80 causes an accident or in a casewhere it is involved in an accident. Further, the sensor 34 may beconfigured to detect a speed, etc. of the vehicle. The display unit 35may be a display device that reproduces the video data recorded in theexternal recording device 5. The speaker 36 is configured to reproducethe audio data recorded in external recording device 5. The speaker 36includes an audio amplification unit and a sound processing unit (notshown) before the input of the speaker 36 and the speaker 36 includesthese units even when it is only indicated as “speaker 36.”

The communication unit 37 is configured to transmit or receive data toor from the external recording device 5. Specifically, the transmissionunit 38 transmits data to the external recording device 5 and thereception unit 39 receives the data transmitted from the externalrecording device 5. The communication unit 37 may be connected to anetwork using, for example, wireless local area network (LAN)communication scheme. Alternatively, the communication unit 37 may beconnected to a network using wireless communication standards such asLTE (Long Term Evolution). The transmission unit 38 performs, forexample, modulation processing, etc. on the imaging data that has beenoutput from the control unit 81 and transmits the wireless data that hasbeen generated as a result of the processing to the external recordingdevice 5. Also, the reception unit 39 performs, for example,demodulation processing, etc. on the wireless data that has beentransmitted from the external recording device 5 and outputs the imagingdata that has been generated as a result of the processing onto thecontrol unit 81. Alternatively, the modulation processing on the imagingdata and the demodulation processing on the wireless data may be carriedout by the transmission control unit 28 and the reception control unit29 in the control unit 81.

The recording control unit 23 converts the imaging data stored in thebuffer memory 24 into a file and outputs the imaging data in the fileformat to the transmission control unit 28. The transmission controlunit 28 transmits the imaging data via the transmission unit 38 to theexternal recording device 5. When outputting of the imaging data storedin the buffer memory 24 to the transmission control unit 28 is caused bythe event that has been detected by the event detection unit 22, therecording control unit 23 outputs the imaging data acquired from thebuffer memory 24 to the transmission control unit 28. The imaging dataacquired from the buffer memory 24 includes video data and the audiodata. In other words, the recording control unit 23 migrates the imagingdata acquired from the buffer memory 24 to the external recording device5 via the transmission control unit 28 and the transmission unit 38. Inother words, the recording control unit 23 records the imaging dataacquired from the buffer memory 24 in the external recording device 5.When outputting of the imaging data stored in the buffer memory 24 tothe transmission control unit 28 is caused by the event that has beendetected by the event detection unit 22, the recording control unit 23outputs the imaging data acquired from the buffer memory 24 on an as-isbasis to the transmission control unit 28. Specifically, the recordingcontrol unit 23 generates the moving image file including the video dataand the audio data from the imaging data stored in the buffer memory 24and outputs the moving image file to the transmission control unit 28.

When outputting of the imaging data stored in the buffer memory 24 tothe transmission control unit 28 is not caused by the event that hasbeen detected by the event detection unit 22, the recording control unit23 outputs data that only includes the video data to the transmissioncontrol unit 28 among the pieces of the imaging data acquired from thebuffer memory 24. That is, the recording control unit 23 outputs theimaging data that includes video data but does not include audio data tothe transmission control unit 28. In other words, the recording controlunit 23 records the data obtained by erasing audio data from the imagingdata from the buffer memory 24 onto the external recording device 5.

Specifically, the recording control unit 23 replaces the audio data bysoundless audio data for the imaging data stored in the buffer memory 24to generate a moving image file with the video data, and outputs themoving image file to the transmission control unit 28.

When the recording control unit 23 outputs the imaging data includingthe video data and the audio data to the transmission control unit 28,then the recording control unit 23 may output imaging data caused by anevent, that is, imaging data including video data and audio data to thetransmission control unit 28 as overwrite-prohibited data. For example,the recording control unit 23 may designate the address of the memoryarea in the external recording device 5 where overwriting of data isprohibited so as to output the imaging data to the transmission controlunit 28. Alternatively, the recording control unit 23 may specify flaginformation or the like indicating that overwriting is prohibited in theheader or the payload of the imaging data.

Also, when the recording control unit 23 outputs the imaging data thatis not caused by an event, i.e., imaging data from which the audio datais erased so that it only includes the video data, to the transmissioncontrol unit 28, then the recording control unit 23 may output imagingdata that only includes video data to the transmission control unit 28as overwritable data. For example, the recording control unit 23 maydesignate the address of the memory area in the external recordingdevice 5 where overwriting of data is allowed and output the imagingdata to the transmission control unit 28. Alternatively, the recordingcontrol unit 23 may specify flag information indicating that overwritingis allowed in the header or payload of the imaging data.

The reproduction control unit 25 acquires the imaging data recorded inthe external recording device 5 and outputs the video data based on theacquired imaging data to the display unit 35, and output the audio databased on the acquired imaging data to the speaker 36, etc. The receptioncontrol unit 29 outputs the imaging data output from the reception unit39 to the reproduction control unit 25. That is, the reproductioncontrol unit 25 receives the imaging data that has been transmitted fromthe external recording device 5 via the reception unit 39 and thereception control unit 29.

While FIG. 17 illustrates a configuration in which the recording device80 includes the reproduction control unit 25, the reception control unit29, the display unit 35, and the speaker 36, a reproduction device orthe like different than the recording device 80 may include thereproduction control unit 25, the reception control unit 29, the displayunit 35, and the speaker 36. In other words, the recording device 80 maynot include the reproduction control unit 25, the reception control unit29, the display unit 35, or the speaker 36. That is, a reproductiondevice or the like that includes the reproduction control unit 25, thereception control unit 29, the display unit 35, and the speaker 36 mayreproduce the data recorded in the external recording device 5. Forexample, the reproduction device or the like may be a device thatreproduces data recorded in a portable recording medium such as anoptical disc or a card-type recording medium. The data recorded in theexternal recording device 5 may be migrated to the portable recordingmedium.

Here, the relationship between the data output to the transmissioncontrol unit 28 and the data recorded in the buffer memory 24 will bedescribed with reference to FIG. 18 . The horizontal axis indicated inFIG. 18 indicates the passage of time. Each of D−4 to D+2 indicates apiece of the imaging data imaged in a predetermined period. In FIG. 18 ,D−4 is the least recently imaged imaging data and D+2 is the mostrecently imaged imaging data. The predetermined period may be, forexample, several seconds, several tens of second, several minutes, andthe like.

The imaging data that has been acquired by the imaging data acquisitionunit 21 is immediately output to the buffer memory 24. As a result, FIG.18 illustrates a configuration in which the imaging data that has beenacquired by the imaging data acquisition unit 21 is stored on an as-isbasis in the buffer memory 24. In other words, FIG. 18 illustrates aconfiguration in which the particular point of time at which the imagingdata acquisition unit 21 acquired the imaging data and the particularpoint of time at which the imaging data is stored in the buffer memory24 are substantially in agreement with each other. The substantialagreement in this context means may also include a case where theparticular point of time at which the imaging data acquisition unit 21acquired the imaging data is not completely in agreement with theparticular point of time at which the imaging data is stored in thebuffer memory 24. For example, the substantial agreement may encompass acase where the particular point of time at which the imaging data isstored in the buffer memory 24 may be delayed relative to the particularpoint of time at which the imaging data acquisition unit 21 acquired theimaging data. Meanwhile, the imaging data output to the transmissioncontrol unit 28 is temporarily stored in the buffer memory 24 andsubsequently output to the transmission control unit 28 by the recordingcontrol unit 23. As a result, the particular point of time at which theimaging data acquired by the imaging data acquisition unit 21 is storedin the buffer memory 24 is different from the particular point of timeat which it is output to the transmission control unit 28. Specifically,the particular point of time at which the imaging data is output to thetransmission control unit 28 is later than the particular point of timeat which the imaging data is stored in the buffer memory 24.

t1 to t6 indicate the time. The recording control unit 23 determineswhether or not an event occurred in the past predetermined periods atthe time t1 to the time t6. For example, the recording control unit 23determines, at the time t2, whether or not an event occurred in theperiod from the time t1 to the time t2. The recording control unit 23likewise determines, at other time points, whether or not an eventoccurred. In FIG. 2 , the recording control unit 23 at the time t1 tothe time t3 and at the time t5, determines that no event has occurred.Also, the recording control unit 23 at the time t4 determines that anevent has occurred at the time t6 in a period from the time t3 to thetime t4.

When the recording control unit 23 has determined, for example, at thetime t2, that no event has occurred in the period from the time t1 tothe time t2, the recording control unit 23 erases the audio data fromthe imaging data D−2 stored in the buffer memory 24, in other words,makes the audio data of the imaging data D−2 soundless, converts theimaging data which now includes only the video data into a file andoutputs it to the transmission control unit 28. On the other hand, therecording control unit 23 determines at the time t4 that the eventoccurred at the time t6 in the period from the time t3 to the time t4.In this case, the recording control unit 23, converts the data D storedin the buffer memory 24 into a file on an as-is basis without erasingaudio data from the data D acquired at the time t6 by the imaging dataacquisition unit 21, and outputs it to the transmission control unit 28.

While FIG. 18 illustrates a configuration in which the imaging datastoring of which is completed to the buffer memory 24 is instantaneouslyoutput to the transmission control unit 28, the particular point of timeat which the imaging data recorded in the buffer memory 24 is output tothe transmission control unit 28 is not limited to the one illustratedin FIG. 18 . For example, the recording control unit 23 may acquire theimaging data that is being stored into the buffer memory 24 and outputthe acquired imaging data to the transmission control unit 28.Alternatively, when storing of the imaging data into the buffer memory24 has been completed, the recording control unit 23 may output the sameimaging data to the transmission control unit 28 after a lapse of apredetermined period after the time point at which the storing of theimaging data was completed. Here, it is intended that the imaging datacorresponds to any one of D−4 to D+2 illustrated in FIG. 18 .

Also, FIG. 18 illustrates a configuration in which the recording controlunit 23 outputs only the imaging data acquired by the imaging dataacquisition unit 21 in a period including the time point at which theevent occurred without erasing the audio data to the transmissioncontrol unit 28. The recording control unit 23 is not limited to thisand, for example, may output a piece of imaging data acquired by theimaging data acquisition unit 21 in a period prior to the periodincluding the time point at which the event occurred without erasing theaudio data to the transmission control unit 28 in addition to theimaging data acquired by the imaging data acquisition unit 21 in aperiod including the time point at which the event occurred. Forexample, the recording control unit 23 may output, at the time t6, dataD−1 to the transmission control unit 28 without erasing audio data inaddition to the data D acquired by the imaging data acquisition unit 21.

Also, even in a case where the recording control unit 23 determines thatno event has occurred, the recording control unit 23 may output to thetransmission control unit 28 the imaging data acquired in a period priorto the latest period with its audio data erased in addition to theimaging data acquired in the latest period stored in the buffer memory24.

In FIG. 18 , the period in which data D−4 to data D−1 are output to thetransmission control unit 28 and the period in which data D+1 is outputare defined as audio data erasure period and the period in which data Dis output to the transmission control unit 28 is defined as an audiodata non-erasure period. Next, the flow of the transmission processingfor transmitting imaging data according to the tenth embodiment will bedescribed with reference to FIG. 19 . First, the imaging dataacquisition unit 21 outputs the imaging data including the video dataand the audio data to the buffer memory 24 and the buffer memory 24starts storing of the imaging data (S101). Next, the recording controlunit 23, in starting outputting of the imaging data stored in the buffermemory 24 to the transmission control unit 28, determines whether or notan event has occurred (S102). Specifically, the recording control unit23 determines whether or not an event occurred in a period of imaging ofthe imaging data to be output to the transmission control unit 28. Forexample, the recording control unit 23 determines whether or notoccurrence of an event has been detected by the event detection unit 22in a period of imaging of the imaging data to be output to thetransmission control unit 28.

The recording control unit 23 outputs the imaging data whose period ofimaging includes the particular point of time at which the eventoccurred to the transmission control unit 28 (S103). The transmissioncontrol unit 28 transmits the output imaging data to the externalrecording device 5 via the transmission unit 38. The imaging data outputin the step S13 is a moving image file that includes the video data andthe audio data. In other words, the recording control unit 23 convertsthe imaging data stored in the buffer memory 24 into a file withouterasing the audio data therefrom and outputs the imaging data to thetransmission control unit 28.

When the recording control unit 23 determines that no event hasoccurred, the recording control unit 23 erases the audio data from theimaging data imaged in a period in which no event occurred and outputsthe imaging data that only includes the video data to the transmissioncontrol unit 28 (S104). The imaging data output in the step S104 is amoving image file that includes video data and audio data that is madeto be soundless. In other words, the recording control unit 23 erasesaudio data from the imaging data stored in the buffer memory 24 andconverts it into a file and outputs the imaging data to the transmissioncontrol unit 28. The transmission control unit 28 transmits the outputimaging data to the external recording device 5 via the transmissionunit 38.

The recording control unit 23, after having output the imaging datastored in the buffer memory 24 to the transmission control unit 28 inthe step S103 or S104, determines whether or not outputting of theimaging data in a predetermined period has been completed (S105). Thepredetermined period may be the period of imaging of the respectivepieces of imaging data D−4 to D+2 described in FIG. 18 . For example,the recording control unit 23 may determine whether or not a piece ofimaging data D−2 that is not output to the transmission control unit 28remains to exist in the buffer memory 24 while the imaging data D−2 isbeing output to the transmission control unit 28. When the recordingcontrol unit 23 determines that the imaging data D−2 that is not outputto the transmission control unit 28 does not remain to exist in thebuffer memory 24, then the recording control unit 23 may determine thatthe outputting of the imaging data in a predetermined period has beencompleted. When the recording control unit 23 determines that theimaging data D−2 that is not output to the transmission control unit 28remains to exist in the buffer memory 24, then the recording controlunit 23 continues outputting of the imaging data D−2.

Next, the recording control unit 23 determines whether or not outputtingof all the pieces of imaging data stored in the buffer memory 24 hasbeen completed (S106). When the recording control unit 23 determinesthat the outputting of all the pieces of imaging data stored in thebuffer memory 24 has been completed, then the recording control unit 23terminates the processing. The case where no imaging data that is notoutput to the transmission control unit 28 exists in the buffer memory24 may include, for example, a case where the driver performed anoperation to stop the imaging, a case where the engine has stopped andthe imaging has been stopped, and other cases.

When the recording control unit 23 determines that outputting of all thepieces of imaging data that were stored in the buffer memory 24 has notbeen completed, the recording control unit 23 repeatedly carries out theprocessing steps of the step S101 and the subsequent steps.

As described in the foregoing, the recording device 80 according to thetenth embodiment can transmit video data and the audio data to theexternal recording device 5 for the imaging data whose imaging periodincludes the particular point of time at which the event occurred. Also,with regard to the imaging data imaged in a period in which no event hasoccurred, the recording device 80 can erase the audio data from theimaging data and transmit only the video data to the external recordingdevice 5. The video data transmitted to the external recording device 5is stored by the external recording device. By virtue of this, therecording device 80 makes it possible for the imaging data at the timeof occurrence of an event such as a traffic accident to contribute toidentification of the cause of the accident because the imaging dataincludes the video data and the audio data. On the other hand, therecording device 80 erases audio data that may include speeches of adrivers or conversations between the driver and the passenger and thelike from the imaging data in the period in which no event has occurredand thus can protect the privacy of the driver and the passenger.

Also, since the imaging data is recorded in the external recordingdevice 5, it is made possible to prevent corruption and loss of theimaging data even when the vehicle or drive recorder is damaged due tothe accident or the like.

Eleventh Embodiment

Next, the flow of the transmission processing for transmitting theimaging data according to the eleventh embodiment will be described withreference to FIG. 20 . FIG. 20 focuses on illustration of the processesdifferent from those in FIG. 19 .

Since the step S111 is the same as or similar to the step S101 of FIG.19 , detailed explanations thereof will not be repeated. Next, therecording control unit 23 determines whether or not an event hasoccurred at the start of outputting of the imaging data stored in thebuffer memory 24 to the transmission control unit 28 (S112).

Here, the event that is detected by the event detection unit 22 isdescribed in detail with reference to FIG. 21 . The information acquiredby the event detection unit 22 or a device that detect the sameinformation is described in the SENSING column in FIG. 21 . Theacceleration sensor detects acceleration information or impactinformation of the vehicle and outputs it to the event detection unit22. The user operation refers to operation of the recording device 80 bythe user and reception of the operation to manually start the recordingcaused by an event without relying on the sensor, etc. The steeringinformation is information on steering wheel operation by the driveracquired, for example, via a CAN network. The speed information is speedinformation of the vehicle acquired, for example, by a CAN network. Thevolume is, for example, information indicative of the sound level of theuser of the vehicle.

In the EVENT column, an example of an event determined on the basis ofthe information acquired by the event detection unit 22 or the like isdescribed. For example, when the acceleration detected by theacceleration sensor is equal to or larger than the threshold 1 and equalto or larger than the threshold 2 indicative of a collision, then theevent detection unit 22 determines that the vehicle has collided with ahuman or an object. The threshold 2 is defined to be a value larger thanthe threshold 1. Alternatively, when the waveform of the acceleration isthe one that indicates a collision, the event detection unit 22 maydetermine that the vehicle has collided with a human or an object. Also,when the acceleration detected by the acceleration sensor is equal to orlarger than the threshold 1 and lower than the threshold 2, then theevent detection unit 22 determines that the vehicle has made suddenacceleration or sudden deceleration. Alternatively, when the waveform ofthe acceleration is not the one that indicates a collision, the eventdetection unit 22 may determine that the vehicle has made suddenacceleration or sudden deceleration. Also, the event detection unit 22detects operation of the operation unit of the recording device 80 andan instruction to start recording caused by an event. Also, in a casewhere the speed of rotation of the steering wheel exceeds apredetermined value, in a case where the amount of rotation of thesteering wheel exceeds a predetermined value, or in other cases, theevent detection unit 22 determines that the driver has turned thesteering wheel suddenly. Also, when the speed of the vehicle exceeds apredetermined value, the event detection unit 22 determines that thevehicle is in a state of overspeed. Also, when the sound level of theuser of the vehicle exceeds a predetermined value, the event detectionunit 22 determines that a human trouble has occurred in the vehicle.

In the EVENT LEVEL column, the levels of the individual events aredescribed. For example, an event level of an event such as collision andhuman trouble are set to high and the event levels of other events areset to low. The recording control unit 23 determines the type of theimaging data to be transmitted to the external recording device 5 on thebasis of the event level.

In the TRANSMISSION DATA column, the data which the recording controlunit 23 transmits to the external recording device 5 via thetransmission control unit 28 and the transmission unit 38 is described.For example, when the event level is set to high, then the recordingcontrol unit 23 transmits the video data and the audio data. Also, whenthe event level is set to low, then the recording control unit 23transmits only the video data. Also, when the event detection unit 22determined the event using the information detected by the accelerationsensor, then the recording control unit 23 may additionally transmit theacceleration information. Further, when the event detection unit 22 hasdetermined the event using the speed information, then the recordingcontrol unit 23 may additionally transmit the speed information.

Referring back to FIG. 20 , when occurrence of an event has beennotified from the event detection unit 22, the recording control unit 23determines whether or not the event level is high (S113). When the eventdetection unit 22 has detected the event, the event detection unit 22notifies the content of the event described in the EVENT column of FIG.21 and its event level to the recording control unit 23. When therecording control unit 23 has determined that the event level is high,the recording control unit 23 outputs the imaging data whose imagingperiod includes the particular point of time at which the event with itsevent level set to high occurred to the transmission control unit 28(S114). The imaging data output in the step S114 is a moving image fileincluding the video data and the audio data.

When occurrence of an event has not been notified from the eventdetection unit 22 and the recording control unit 23 has determined inthe step S112 that no event occurred and determined in the step S113that the event level of the event that occurred is not high, then therecording control unit 23 carries out the processing defined at the stepS115. In the step S115, the recording control unit 23 erases the audiodata from the imaging data imaged in a period where no event occurred,or the imaging data including the particular point of time at which theevent occurred, and outputs the imaging data that only includes thevideo data to the transmission control unit 28.

Since the steps S116 and S117 are the same as or similar to the stepsS105 and S106 of FIG. 19 , detailed explanations thereof will not berepeated.

As described in the foregoing, the recording device 80 according to theeleventh embodiment can determine, in accordance with the event level ofthe event that occurred, whether the video data and the audio datashould be transmitted to the external recording device 5 or only thevideo data should be transmitted to the external recording device 5. Forboth of the high and low event levels, the flag information is specifiedthat indicates prohibition of overwriting as the imaging data caused bythe event. Also, with regard to the data recorded by the externalrecording device 5, the imaging data that is not caused by an event isrecorded in an overwritable manner without including the audio data; andwith regard to the imaging data caused by the event, if the event levelis high, then audio data and video data are recorded; and if the eventlevel is low, then the imaging data is recorded without the audio dataincluded therein. By virtue of this, among the pieces of imaging datathat have been transmitted from the recording device 80 to the externalrecording device 5 to be recorded as overwrite-prohibited data, thevideo data recording occurrence of an accident or a trouble is recordedas data whose audio data can be referred to in addition to the videodata for the purpose of identification of the cause of the accident orthe trouble, and the video data recording the operation state of thevehicle or the like is recorded without its audio data included therein,so that it is made possible to protect privacy of the driver and thepassenger in relation to the imaging data whose recording is caused byan event.

Twelfth Embodiment

Next, an example of a configuration of a recording device 90 accordingto the twelfth embodiment will be described with reference to FIG. 22 .The recording device 90 has a control unit 91 instead of the controlunit 81 of the recording device 80 of FIG. 17 . Also, the control unit91 has a configuration in which a volume level acquisition unit 92 isadded to the control unit 81 of FIG. 17 . The same reference signs aregiven to the same features of recording device 90 as those of therecording device 80, and detailed explanations thereof will not berepeated. The following explanations focus on the features of therecording device 90 different from those of the recording device 80. Therecording device 90 may be configured to include the constituentcomponents realized by the control unit 91 in the same or similar manneras the recording device 80.

Specifically, the recording device 90 includes the imaging dataacquisition unit 21, the event detection unit 22, the recording controlunit 23, the transmission control unit 28, and the volume levelacquisition unit 92.

The volume level acquisition unit 92 acquires the information on thevolume level from the audio data generated by the microphone 32. Thevolume level acquisition unit 42 may acquire the information on thevolume level from the audio data acquired by the imaging dataacquisition unit 21. The volume level may be information indicative ofthe volume of, for example, a sound. The volume level acquisition unit42 outputs the information on the volume level to the event detectionunit 22. Specifically, the information on the volume level may includethe identification information to identify the audio data.

While FIG. 22 illustrates a configuration in which the volume levelacquisition unit 92 is arranged between the microphone 32 and the eventdetection unit 22, the volume level acquisition unit 42 may be arrangedbetween the imaging data acquisition unit 21 and the event detectionunit 22.

The recording control unit 23 determines whether or not the audio datashould be erased from the imaging data in accordance with the volumelevel regarding the audio data. For example, the threshold 1 for thevolume level is defined between the volume at a level of normalconversation and a loud voice above the level of normal conversation.That is, the threshold 1 is used to identify the normal conversationlevel and volume levels equal to or higher than that. The loud voiceabove the level of normal conversation may be, for example, a humanscream or shouting voice, etc. The volume level exceeding the threshold1 indicates occurrence of the human trouble illustrated in FIG. 21 .That is, when the volume level exceeds the threshold 1, the occurrenceof the human trouble is detected by the event detection unit 22 and theevent level is set to high.

If the volume level is lower than the threshold 1, the recording controlunit 23 erases the audio data from the imaging data and transmits onlythe video data to the external recording device 5. That is, if thevolume level is lower than the threshold 1, no event is detected.

Since the recording control unit 23 determines whether or not the audiodata should be erased from the imaging data on the basis of thethreshold 1, privacy of the driver or the passenger can be protected.

Next, the flow of the transmission processing to transmit the imagingdata according to the twelfth embodiment will be described. Since thetransmission processing to transmit the imaging data according to thetwelfth embodiment is the same as or similar to that of FIG. 20 , theflow of the transmission processing to transmit the imaging dataaccording to the twelfth embodiment will be described with reference toFIG. 20 . The transmission processing to transmit the imaging dataaccording to the twelfth embodiment is processing that proceeds mainlyin accordance with the volume level. The content related to theprocessing using the volume level in FIG. 20 will be described below.

In the step S112, the recording control unit 23 determines whether ornot an event associated with human trouble has been notified from theevent detection unit 22. Specifically, the event detection unit 22determines whether or not a volume level exceeding the threshold 1 hasbeen acquired from the volume level acquisition unit 92. When the volumelevel acquired by the volume level acquisition unit 92 exceeds thethreshold 1, the event detection unit 22 notifies the occurrence of theevent associated with human trouble to the recording control unit 23.When the volume level acquired by the volume level acquisition unit 92is lower than the threshold 1, the event detection unit 22 determinesthat no event associated with human trouble has occurred.

Further, in the step S113, the recording control unit 23 determineswhether or not the event level of the event notified from the eventdetection unit 22 is high. As illustrated in FIG. 21 , the event levelof the event associated with human trouble is set to high. As a result,when the recording control unit 23 in the step S112 is notified aboutthe occurrence of a human trouble, the recording control unit 23determines that the event level is high. Also, when the event detectionunit 22 has multiple thresholds regarding the volume level, the eventdetection unit 22 may set the event levels regarding the human troubleto high or low in accordance with the volume level. In such a case, therecording control unit 23 determines in the step S112 that a humantrouble has occurred as an event and, in the step S113, may determinethat the event level is not high.

Since the processing steps other than the steps S112 and S113 are thesame as or similar to those that have already been described, detailedexplanations thereof will not be repeated.

As described in the foregoing, by using the recording device 90according to the twelfth embodiment, it is made possible to determinewhether or not the audio data should be erased from the imaging data inaccordance with the volume level. By virtue of this, if the volume levelfalls within the range that would not correspond to a human trouble, itis made possible to provide records that do not include audio data andthereby ensure privacy.

In the above-described example, the program can be stored using varioustypes of non-transitory computer readable media and supplied to acomputer. Non-transitory computer readable media include various typesof tangible storage media. Examples of non-transitory computer readablemedia include a magnetic recording medium (e.g., a flexible disc, amagnetic tape, and a hard disk drive), a magneto-optical recordingmedium (e.g., a magneto-optical disc), a read only memory (CD-ROM) unit,a CD-R unit, a CD-R/W unit, semiconductor memory unit (e.g., a mask ROMunit, a programmable ROM (PROM) unit, an erasable PROM (EPROM) unit, aflash ROM unit, and a random access memory (RAM) unit). Also, theprogram may be supplied to the computer by various types of transitorycomputer readable media. Examples of transitory computer readable mediainclude electrical signals, optical signals, and electromagnetic waves.A transitory computer readable medium can supply a program to a computervia a wired communication channel such as an electrical wire and anoptical fiber, or a wireless communication channel.

It should be noted that the present disclosure is not limited to theabove-described embodiments and can be appropriately modified as long asits scope is not deviated from.

The present application can be adopted to a recording device thatrecords imaging data.

What is claimed is:
 1. A recording device comprising: an imaging data acquisition unit configured to acquire imaging data including video data and audio data imaging an inside of a vehicle or an outside of the vehicle to which the recording device is mounted; an event detection unit configured to detect occurrence of an event for the vehicle; a recording control unit configured to record first imaging data in a recording unit when recording of the imaging data in the recording unit is caused by the event detected by the event detection unit, and record second imaging data in the recording unit when recording of the imaging data in the recording unit is not caused by the event detected by the event detection unit; and a reproduction control unit configured to reproduce the video data and the audio data included in the first imaging data when reproducing the first imaging data, and reproduce the video data included in the second imaging data without reproducing or outputting the audio data included in the second imaging data when reproducing the second imaging data.
 2. The recording device according to claim 1, further comprising a speech analysis unit configured to perform speech analysis on the audio data included in the imaging data acquired by the imaging data acquisition unit, wherein the reproduction control unit is configured to reproduce the video data included in the second imaging data without reproducing or outputting the audio data included in the second imaging data when the reproduction control unit reproduces the second imaging data and the speech is included in the audio data.
 3. The recording device according to claim 1, further comprising a passenger detection unit configured to detect presence of absence of a passenger in the vehicle to which a recording device is mounted, wherein the reproduction control unit is configured to reproduce the video data included in the second imaging data without reproducing or outputting the audio data included in the second imaging data when the reproduction control unit reproduces the second imaging data and the second imaging data is acquired when the passenger is detected.
 4. The recording device according to claim 1, further comprising a volume level acquisition unit configured to acquire the volume level of the audio data included in the imaging data acquired by the imaging data acquisition unit, wherein the reproduction control unit is configured to reproduce the video data included in the second imaging data without reproducing or outputting the audio data included in the second imaging data when the reproduction control unit reproduces the second imaging data and the volume level is lower than a threshold 1 defined between a volume at a level of normal conversation and a loud voice above the level of normal conversation.
 5. A reproducing method in a recording device, the reproducing method comprising: acquiring imaging data including video data and audio data imaging an inside of a vehicle or an outside of the vehicle to which the recording device is mounted; detecting occurrence of an event for the vehicle; recording first imaging data in a recording unit when recording of the imaging data in the recording unit is caused by the detected event, and record second imaging data in the recording unit when recording of the imaging data in the recording unit is not caused by the detected event; and reproducing the video data and the audio data included in the first imaging data when reproducing the first imaging data, and reproduce the video data included in the second imaging data without reproducing or outputting the audio data included in the second imaging data when reproducing the second imaging data. 